AB1513 MANAGEMENT OF RETROPERITONEAL FIBROSIS PATIENTS: A SCOTTISH COHORT OBSERVATIONAL STUDY
Authors: E. Qian, D. S. Sahni, P. Lyons, D. Porter, H. Harris
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> Retroperitoneal fibrosis (RPF) is a rare condition characterised by the inflammation and fibrosis of tissues in the retroperitoneum. Often presenting non-specifically with a variable picture of abdominal pain, constipation, and systemic symptoms of malaise, fever, and weight loss. RPF may also present with severe obstructive uropathy. Initial response to steroids is usually good, but a significant proportion of patients relapse. Evidence for second line treatment is scarce, and a variety of immunosuppressive therapies, such as rituximab, have been used. Surgical intervention and interventional radiology may be useful in treating acute ureteric obstruction and preserving renal function. <h3>Objectives</h3> As an orphan disease without, traditionally, a clear home speciality, retroperitoneal disease is likely underdiagnosed and undertreated especially in those who do not have ureteric obstruction. We characterised patients with retroperitoneal fibrosis across West and South-East Scotland to better understand these patients and their outcomes. <h3>Methods</h3> Patients were previously identified in East Scotland by contacting rheumatologists and by searching the urological stent registry from 2019 to 2022. The method was replicated in the West of Scotland though was less successful as the urological stent register did not record diagnoses, and clinicians did not have an accessible database for this condition. A further avenue of patient identification was then pursued. All available radiological reports and their attached clinical data on the request from 2006 to September 2022 were searched for the term "RPF" and "retroperitoneal fibrosis". Patients were included if they were given a clinical diagnosis of retroperitoneal fibrosis. Patients were excluded if RPF was concurrent with metastatic malignancy, associated with infection or other secondary cause. Patient data was acquired from their electronic records. <h3>Results</h3> 78 patients were identified: 56 in the West of Scotland and 22 in the South-East. Patient demographics are shown in Table 1. The diagnosis was most often made by CT scan. The estimated annual incidence in the last 10 years 2.2 is per million population in the West and 1.6 per million population in the East, for catchment populations of 1.2 million and 0.9 million, respectively. Treatment was heterogenous in both groups. Renal outcomes for these patients were interrogated. Patients were classified as having lost renal function if there was either biochemical or radiological evidence. <h3>Conclusion</h3> The literature suggests renal impairment is variable in retroperitoneal fibrosis with only 32% of patients with abnormal creatinine reported in one study which is much lower than our results. The current literature is sparce for alternative therapies. More work is required in determining efficacy for more recent therapies such as rituximab to further the treatment of this orphan disease and improve patient outcomes. <h3>References</h3> [1]Vaglio A, Maritati F. Idiopathic Retroperitoneal Fibrosis. J Am Soc Nephrol. 2016;27:1880-9. [2]Kermani TA, Crowson CS, Achenbach SJ, Luthra HS. Idiopathic retroperitoneal fibrosis: a retrospective review of clinical presentation, treatment, and outcomes. Mayo Clin Proc. 2011;86:297-303. <h3>Acknowledgements</h3> Acknowledgements to the Rheumatology and Urology team at NHS Lothian and NHS GGC for patient identification. Acknowledgements to Greater Glasgow and Clyde Safe Haven Data Team for their assistance with accessing databases for patient identification. <h3>Disclosure of Interests</h3> None Declared.